# Shell Command Structure Summary

### Arguments (i.e. Positional Arguments)

Positional arguments are passed as-is after the command name. Order matters.

`cat file1.txt file2.txt`

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### Options (Named Arguments)

Options are named arguments and come in two forms:

- **Short**: One-letter options are preceeded by a `-` with values placed after (separated by a space).

  `git commit -m "Fix"`

- **Long**: Multi-letter options are preceeded by a `--` with values placed after (separated by a `=` or by a space).

  `git commit --message="Fix"` 🟰 `git commit --message "Fix"`
  
> **Note:** Spaces aren't *required* after options, but are *encouranged* for readability, because `git commit -m"Fix"` looks cramped.

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### Flags

Flags represent boolean values. They are options which don't take a value and can be long or short.

`git commit --dry-run -v`

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### Combining Short Flags

When using multiple short flags, you can combine them into one.

`ls -a -g -h` 🟰 `ls -agh` 🟰 `ls -gha`

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### Ordering

The order of options/flags does not matter.

`ls -a -g` 🟰 `ls -g -a`

**However**, some commands require all options/flags to come before positional arguments.

❌ `ls my-dir -a`  
✅ `ls -a my-dir`

Thankfully, most modern commands are agnostic.

`git add a.js -v` 🟰 `git add -v a.js`

I prefer to put positional arguments before options/flags when possible, as I find it easier to read.

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### Quotes

Quotes are only required for strings that contain special characters (e.g. spaces).

❌ `git commit -m Fix thing`  
✅ `git commit -m "Fix thing"`  
✅ `git commit -m Fix`

> **Note**: When writing npm scripts, prefer double quotes `"` to single `'` for better cross-compatability with Windows.

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### Subcommands

Many modern commands use a command-subcommand structure, like git. In the following example, `git` is the root command, and `commit` is the subcommand.

`git commit -m "Hi"`

### Summary

![CLI Anatomy](https://user-images.githubusercontent.com/14965732/229198794-6e2ce6b7-fe56-4bf7-8ddf-b1619af00bbd.png)